GUAC-958: Work around iOS 7 visibility issue (again) by using object instead of iframe. The resize sensor needs to be where it used to be in the DOM for proper operation.

guacamole/src/main/webapp/app/client/directives/guacClient.js

@@ -339,7 +339,7 @@ angular.module('client').directive('guacClient', [function guacClient() {
             });
             
             // If the element is resized, attempt to resize client
-            resizeSensor.contentWindow.addEventListener('resize', function mainElementResized() {
+            resizeSensor.contentDocument.defaultView.addEventListener('resize', function mainElementResized() {
 
                 // Send new display size, if changed
                 if (client && display) {